1. Field of the Invention
The present invention relates to a gas cylinder and more particularly to a gas cylinder capable of improving sealing characteristics of the gas cylinder, which is important from viewpoint of reliability in performance and operation of the gas cylinder, and of improving convenience in handling upon production of the gas cylinder in production spot.
2. Background of the Related Art
A gas cylinder is an apparatus for use in an automobile, a table, a chair, for making a product more conveniently used, by reducing impulse applied from the outside, or by applying restoring force in one direction. The gas cylinder according to the present invention does not exclude application to different usage such as an automobile, but the gas cylinder more preferably applicable to a chair, will be described as an example.
The gas cylinder is an apparatus for exerting force in one direction the length of the cylinder increases, and in case that a user does not sit on a chair, upon operation of a lever, the length of the cylinder increases by extending force due to air flowing in one direction.
Also, in case that a user sits on a chair, upon operation of a lever, extending force of a spring is suppressed by a weight of a user and the length of the cylinder is reduced.
Construction of a chair in which a gas cylinder of a related art is adopted, is described in detail in U.S. Pat. No. 6,199,952.
In the meantime, the construction of the gas cylinder of a related art will be briefly described in the following. The gas cylinder of a related art includes: a spindle whose inside is filled with gas of high pressure higher than atmospheric pressure; a base tube, to the inside of which the spindle is inserted; a piston whose lower end is fixed in the lower side of the base tube and inserted to the inner space of the spindle. As detailed description of the gas cylinder is known by a plurality of the related arts disclosed, other details will be omitted.
With such construction, the spindle is moved up and down by external force and restoring force due to gas pressure, whereby operation required by the gas cylinder is performed.
In the meantime, the inside of the gas cylinder of a related art is filled with gas of high pressure for operation of the gas cylinder, and the pressure of the gas is considerably higher than the atmospheric pressure. Such high pressure gas filled in the inside of the spindle, has possibility of leaking out even by a small gap. Therefore, sealing structure for preventing such high pressure gas from leaking out, is highly required.
Also, in reality, most of processes are carried out by manual process in the production spot of the gas cylinder. Therefore, it is important point to be resolved in manufacturing process of the gas cylinder to simplify such production process.